Known in the art is a method for the purification of hydrocarbon gases from hydrogen sulfide comprising a heterogeneous-catalytic oxidation of hydrogen sulfide. The catalyst contains aluminium, iron, titanium and zinc oxides. Oxidation is carried out at 220.degree.-260.degree. C. (U.S. Pat. No. 4,519,992). The The method allows the degree of purification of a starting gas of 99.0-99.6% by mass to be achieved, but it is only suitable for the purification of gases having a hydrogen sulfide content of maximum 3% by vol.
Known in the art is a method for the purification of hydrogen sulfide-containing gases containing 4 to 25% by vol. of hydrogen sulfide (German Pat. No. 1,3332563). With this method, hydrogen sulfide-containing gases of such a concentration are subjected to oxidation on solid catalysts in the form of a mixture of nickel, titanium and aluminium oxides. Oxidation is carried out with oxygen used in an amount of 100% of the stoichiometric quantity according to the reaction H.sub.2 S+1/2O.sub.2 .fwdarw.S+H.sub.2 O. In carrying out oxidation on the abovementioned catalyst at 265.degree. C., the starting gas is purified from hydrogen sulfide with the formation of elemental sulfur (sulfur yield amounts to 93.4%). Gaseous sulfur, water vapour and unreacted hydrogen-sulfide-containing gas are fed after oxidation to condensing of sulfur and water, whereafter hydrogen sulfide-containing gas containing about 0.11% by vol. of H.sub.2 S, 0.22% by vol. SO.sub.2, 89.0% by vol. of CO.sub.2, and 10.67% by vol. of H.sub.2 O is subjected to reoxidation with sulfur dioxide to form elemental sulfur on a solid titanium-containing catalyst at 205.degree. C. Finally, the overall degree of hydrogen sulfide recovery in the form of elemental sulfur amounts to 98%, the purified gas containing up to 1 g/nm.sup.3 of pulverulent sulfur.
The prior art method is suitable for the purification of gases containing maximum 25% by volume of hydrogen sulfide. The use of gases with a higher concentration of hydrogen sulfide results in an increase in the adiabatic heating of the catalyst bed to cause an increase in the rate of reaction of sulfur dioxide formation (at a temperature above 350.degree. C.); coking occurs (at a temperature above 500.degree. C.) and cracking of hydrocarbon components takes place (if they are available in the starting gas). The degree of purification in using this method is 97.37% with the hydrogen sulfide content in the starting gas of 11% by vol., the purified gas containing about 2000 mg/nm.sup.3 of hydrogen sulfide and 2000 mg/nm.sup.3 of sulfur dioxide.